* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html, body {
    height: 100%;

    background-image: url("../image/pic.jpeg");
    background-repeat: no-repeat;
    background-position: center;
    background-size: cover;
}

.nav {
    height: 30px;
    background-color: rgb(50,50,50);
    color: white;
    line-height: 30px;
}
.nav span{
    padding-left: 20px;
}
.nav a{
    text-decoration: none;
    color: white;
    float: right;
    padding-right: 20px;
}
.container {
    width: 100%;
    height: calc(100% - 50px);
    display: flex;
    align-items: center;
    justify-content: center;
}